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Biomedical subjects

S M Ascher

Publications and source records attributed to S M Ascher.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hepatosplenic fungal disease: diagnostic accuracy and spectrum of appearances on MR imaging.

OBJECTIVE: We describe our 6-year experience in the prospective examination of patients with suspected hepatosplenic fungal disease to show the diagnostic accuracy of MR imaging and the spectrum of appearances on MR images. SUBJECTS AND METHODS: All patients who underwent MR examination for suspected hepatosplenic fungal disease from January 1990 to January 1997 in three university institutions were included in the study. Patients presented with persistent fever or no response to antibacterial antibiotics. Patients were grouped as acute, subacute treated, and chronic treated, according to the duration of their symptoms. Patients with 2 weeks or fewer of possible infection were acute presentation, patients on antifungal therapy longer than 2 weeks but shorter than 3 months were subacute treated presentation, and patients on antifungal therapy for 3 months or longer or who had completed antifungal therapy and had a history of hepatosplenic fungal disease were chronic treated presentation. MR studies were prospectively interpreted for the presence of hepatosplenic fungal lesions. The appearances of fungal lesions in patients in each category were determined. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detecting lesions in patients with acute presentation were also determined. RESULTS: Sixty-nine patients were included in the study. MR imaging revealed signs consistent with hepatosplenic fungal lesions in 22 (32%) of 69 patients and no demonstration of hepatosplenic lesions in 47 (68%) of 69 patients. In the 60 patients with acute presentation, MR imaging in 13 patients revealed hepatosplenic lesions that were interpreted as fungal disease. True-positive lesions were present in 11 of these 13 patients. These lesions measured less than 1 cm in diameter and were best shown as well-defined high-signal-intensity foci on T2-weighted images. The remaining two of the 13 patients had false-positive lesions; one was shown to have tuberculosis, and the other had graft-versus-host disease. For acute presentation, MR sensitivity was 100%, specificity was 96%, positive predictive value was 85%, negative predictive value was 100%, and accuracy was 97%. In the five patients with subacute presentation, lesions were present that measured less than 1 cm in diameter and were best shown as mildly hyperintense on T1-weighted images. A perilesional ring nearly void of signal intensity was seen on unenhanced and gadolinium-enhanced T1-weighted images in all five patients. The four patients with chronic healed lesions all had lesions that were 1-3 cm in diameter with irregular, angular polygonal margins. These lesions, which were best shown on images obtained immediately after gadolinium administration, appeared as regions of diminished enhancement with no perilesional changes. CONCLUSION: MR imaging has high diagnostic accuracy for the diagnosis of acute hepatosplenic fungal disease. Patients with acute, subacute treated, and chronic healed presentations may have lesions that can be distinguished by their MR appearances.

Acute Disease↗
PubMed1996

MR imaging appearance of the uterus in postmenopausal women receiving tamoxifen therapy for breast cancer: histopathologic correlation.

PURPOSE: To describe the spin-echo and dynamic gadolinium-enhanced magnetic resonance (MR) imaging appearance of the uterus in women receiving tamoxifen. MATERIALS AND METHODS: Thirty-five postmenopausal women with breast carcinoma receiving tamoxifen therapy underwent pelvic MR imaging. T1-weighted, T2-weighted, and dynamic gradient-echo T1-weighted sequences were used. Twenty-seven patients underwent uterine sampling within 3 months of MR imaging. RESULTS: Endometrial width on T2-weighted images ranged from 0.1 to 7.5 cm (mean thickness, 1.1 cm). Two uterine imaging patterns were noted. Patients with pattern 1 findings had homogeneous high signal intensity of the endometrium on T2-weighted images (mean, 0.5 cm) and enhancement of the endometrial-myometrial interface and a signal void in the lumen on gadolinium-enhanced images (18 patients). Patients with pattern 2 findings had heterogeneous endometrial signal intensity on T2-weighted images (mean, 1.8 cm) with enhancement of the endometrial-myometrial interface and latticelike enhancement traversing the endometrial canal on gadolinium-enhanced images (17 patients). Other imaging findings included subendometrial cysts, nabothian cysts, leiomyoma, and adenomyosis. Ten patients with pattern 1 findings had atrophic or proliferative endometria at histopathologic analysis; 12 of the 17 patients with pattern 2 findings had polyps, one of which had a focus of endometrial carcinoma. CONCLUSION: MR imaging of the uterus showed two distinct patterns in women receiving tamoxifen therapy.

Adult↗
PubMed1995

Spontaneous preoperative internal jugular and subclavian vein thrombosis associated with an early-stage synchronous ovarian/endometrial malignancy.

A case of preoperative spontaneous internal jugular/subclavian vein thrombosis documented with magnetic resonance imaging associated with a synchronous stage II ovarian/stage I endometrial malignancy is presented. This unusual deep venous thrombosis site is classically associated with trauma, infection, head and neck malignancies, or central venous catheterization and is rarely associated with distant malignancies. Neck pain and swelling in a gynecologic oncology patient should prompt consideration of this diagnosis.

Carcinoma, Endometrioid↗
PubMed1995

The nonsurgical diagnosis of adenomyosis.

OBJECTIVE: To survey the nonsurgical diagnostic techniques for distinguishing adenomyosis, and to determine whether one technique offers diagnostic advantages. DATA SOURCES: We conducted a thorough search of the MEDLINE data base and identified English-language papers on adenomyosis published during the last 28 years. Reference lists of retrieved articles were also examined for additional source documents. METHODS OF STUDY SELECTION: We reviewed 238 articles. Papers on nonsurgical diagnostic techniques published in peer-reviewed journals were selected for inclusion. DATA EXTRACTION AND SYNTHESIS: We determined nonsurgical diagnostic techniques for distinguishing adenomyosis to be hysterosalpingography, abdominal ultrasound, transvaginal sonography, and magnetic resonance imaging (MRI). Studies were divided into these four categories, reviewed, and summarized accordingly. Recent reports suggest that noninvasive modalities, eg, transvaginal sonography and MRI, have, made possible the nonsurgical diagnosis of adenomyosis. CONCLUSION: Because of its widespread availability and patient tolerance, transvaginal sonography remains the primary screening modality for imaging the female pelvis. However, for cases in which sonography cannot detect adenomyosis, MRI provides a viable alternative and should be the definitive diagnostic modality of choice.

Abdomen↗
PubMed1995

Biliary tract: three-dimensional helical CT without cholangiographic contrast material.

Bile duct anatomy depicted with a three-dimensional (3D) model developed with helical computed tomography (CT) data was compared with cholangiographic depiction. The ductal system was completely displayed from all angles in four of six patients, as well as the stricture and length of bile duct between strictures and the bifurcation in five of six cases. 3D rendering can depict preoperative ductal anatomy.

Adult↗
PubMed1995

Helical (spiral) computed tomography. Implications for imaging of the abdomen.

Dramatic refinements in CT technology are resulting in improved evaluation of the liver, pancreas, and gastrointestinal tract. Further clinical trials are necessary to compare the relative merits of CT versus MR imaging and endoscopic ultrasonography in a wide variety of gastrointestinal diseases.

Gastrointestinal Diseases↗
PubMed1995

Helical (spiral) CT of the pancreas and biliary tract.

Helical scanning offers many advantages for the evaluation of benign and malignant pancreatobiliary disease. This article presents these advantages, recommended screening protocols, and guidelines for the use of three-dimensional rendering of the peripancreatic vessels and bile ducts.

Biliary Tract Diseases↗
PubMed1994

Familial adenomyosis: a case report.

The persuasive data not only illustrate a familial tendency towards adenomyosis but also emphasize that adenomyosis can be diagnosed noninvasively and accurately by MRI. A possible familial predisposition toward or a direct familial cause of adenomyosis warrants further investigation.

Adult↗
PubMed1994

Renal corticomedullary differentiation: observation in patients with differing serum creatinine levels.

PURPOSE: To evaluate renal corticomedullary differentiation (CMD) in patients with differing serum creatinine (sCr) levels. MATERIALS AND METHODS: Ten patients with normal sCr levels (0.9-1.3 mg/dL [80-115 mumol/L]), 14 with mildly elevated levels (1.5-2.9 mg/dL [133-256 mumol/L]), and 15 with elevated levels (> 3.0 mg/dL [265 mumol/L]) were examined with unenhanced T1-weighted fat-suppressed spin-echo (T1FS) and immediate gadolinium-enhanced gradient-echo (Gd-GRE) imaging. RESULTS: Patients with normal sCr levels had CMD on T1FS and Gd-GRE images. Among patients with mildly elevated levels, seven did and seven did not have CMD on T1FS images; all had CMD on Gd-GRE images. Patients with elevated levels had no CMD on T1FS images; 13 had CMD on Gd-GRE images. Two patients with levels above 10.0 mg/dL (884 mumol/L) had no CMD on Gd-GRE images. CONCLUSION: Independent of the cause of elevated sCr level, levels above 3.0 mg/dL result in loss of CMD on T1FS images, while levels above 10.0 mg/dL result in loss of CMD on Gd-GRE images.

Adolescent↗
PubMed1994

Adenomyosis: prospective comparison of MR imaging and transvaginal sonography.

PURPOSE: To prospectively compare conventional spin-echo magnetic resonance (MR) imaging and transvaginal sonography for the diagnosis of adenomyosis. MATERIALS AND METHODS: Twenty women with clinically suspected adenomyosis underwent MR imaging and transvaginal sonography performed within 3 months of each other. Pathologic proof was obtained in all cases. RESULTS: Seventeen patients were proved to have adenomyosis. The correct diagnosis was achieved with MR imaging in 15 of 17 cases. One false-positive and two false-negative diagnoses were made with MR imaging. With transvaginal sonography, nine of 17 cases of adenomyosis were correctly diagnosed. One false-positive and eight false-negative diagnoses occurred. The most frequent cause of false-negative diagnoses with transvaginal sonography was the misinterpretation of adenomyosis as leiomyomas (seven cases). CONCLUSION: MR imaging is significantly better (P < .02) than transvaginal sonography in the diagnosis of adenomyosis.

Adult↗
PubMed1994

Hepatic hemangiomas: a multi-institutional study of appearance on T2-weighted and serial gadolinium-enhanced gradient-echo MR images.

PURPOSE: To define the appearance of hepatic hemangiomas on T2-weighted and serial gadolinium-enhanced gradient-echo magnetic resonance (MR) images. MATERIALS AND METHODS: In four university hospitals, with 1.0- or 1.5-T MR imaging, T2-weighted and T1-weighted gradient-echo images were obtained in 66 adult patients before and at 1, 45, and 90 seconds and 10 minutes after injection of a gadolinium chelate. Hemangiomas were categorized as small (< 1.5-cm-diameter), medium (1.5-5.0-cm), and large (> 5.0-cm) tumors. RESULTS: In all, 154 hemangiomas were depicted (81 small, 56 medium, and 17 large tumors). All 154 lesions were hyperintense on T2-weighted images. Three patterns of contrast enhancement were observed: (a) uniform enhancement at 1 second (35 of 81 small lesions and no medium or large lesions), (b) peripheral nodular enhancement progressing centripetally to uniform enhancement (75 of all 154 lesions), and (c) peripheral nodular enhancement with persistent hypointensity centrally (44 of all 154 lesions, including 16 of 17 large lesions). CONCLUSION: Three patterns of enhancement of hemangiomas were observed. High signal intensity on T2-weighted images provided complementary information.

Adult↗
PubMed1994

Bladder tumor staging: comparison of contrast-enhanced CT, T1- and T2-weighted MR imaging, dynamic gadolinium-enhanced imaging, and late gadolinium-enhanced imaging.

PURPOSE: To evaluate the accuracy of contrast material-enhanced computed tomography (CT), unenhanced T1- and T2-weighted magnetic resonance (MR) imaging, and dynamic gadolinium-enhanced spoiled gradient-echo MR imaging in the staging of bladder cancer. MATERIALS AND METHODS: Thirty-six patients with histologically proved bladder cancer were prospectively examined with CT and MR imaging before tumor resection. Images were evaluated in a blinded fashion. RESULTS: All methods depicted tumors comparably well. Staging was correct in 16 of 29 patients (55%) with CT and 27 of 36 patients (75%) overall with MR imaging. Overstaging was the most common error, and both CT and MR imaging were more accurate for higher-staged tumors. CONCLUSION: CT and MR imaging perform well in the detection of tumors but are less accurate in staging. Dynamic gadolinium-enhanced MR imaging is better than other techniques, but the difference is not statistically significant.

Carcinoma, Transitional Cell↗
PubMed1993

Laparoscopic cholecystectomy. Postoperative sonographic findings.

Seventeen consecutive patients undergoing elective laparoscopic cholecystectomy (LC) were serially evaluated with transabdominal ultrasound before, one day after, and six days after LC to document what, if any, changes occur in the surgical bed and surrounding parenchyma. The most common postoperative finding was focal sonolucency in the hepatic parenchyma adjacent to the gallbladder fossa in six (35%) of 17 patients. Five patients (29%) had postoperative fluid collections in the gallbladder fossa; in four of these five, it was technically difficult to dissect the gallbladder from the liver at the time of original surgery. In one patient the fluid resolved by the sixth postoperative day. It persisted in the remaining four. Two patients had transient ductal dilation and one had pneumobilia. Shadowing and ring-down artifact was identified in 12 patients due to surgical clips in the triangle of Calot. Because gallbladder fossa fluid may persist up to six days after uncomplicated laparoscopic cholecystectomy, caution should be used before attaching significance to isolated imaging findings. Clinical judgement remains the best means of selecting which patients need additional evaluation.

Abdomen↗
PubMed1993

Laparoscopic cholecystectomy: intraoperative ultrasound of the extrahepatic biliary tree and the natural history of postoperative transabdominal ultrasound findings.

Laparoscopic cholecystectomy (LC) has been rapidly embraced as an alternative to conventional open cholecystectomy (OC). While LC is less invasive than OC, it is still a surgical procedure with potential complications such as retained bile duct stones, iatrogenic injury to the bile duct with or without bile leak, hemorrhage, intestinal injury, and abscess formation. This article discusses the feasibility of intraoperative transmural ultrasound of the extrahepatic biliary tree with a 6.2 French catheter-based ultrasound probe and reviews the natural history of postoperative changes in the liver and gallbladder bed with conventional transabdominal ultrasound.

Abdomen↗
PubMed1993

MR imaging of the pancreas.

Magnetic resonance (MR) imaging sequences that reduce image artifact in upper abdominal examinations herald a role for MR in the investigation of pancreatic disease. Sequences that have been successful in imaging the pancreas are T1-weighted breath-hold gradient-echo imaging, which avoids phase artifact caused by respiration, and T1-weighted fat-suppressed spin-echo imaging, which reduces breathing artifact, removes chemical shift artifact, and improves dynamic range of signal intensities. Breath-hold gradient-echo sequences provide useful diagnostic information when used prior to and immediately following bolus intravenous administration of gadopentetate dimeglumine. This review addresses current clinically important roles for MR imaging and emphasizes the detection of islet cell tumors, non-organ-deforming pancreatic ductal adenocarcinomas, and the distinction between chronic pancreatitis and cancer.

Humans↗
PubMed1993

Routine helical CT of the abdomen: image quality considerations.

PURPOSE: Both helical and nonhelical abdominal computed tomographic (CT) scans were obtained to compare image quality, study the effect of patient size and collimation, and compare the frequency of visualization of normal abdominal structures. MATERIALS AND METHODS: The study group consisted of 60 consecutive patients with clinically suspected metastatic malignancy. RESULTS: Both helical and nonhelical image quality was excellent, with equal mean image quality scores of 4.1 on a 5-point scale. In patients weighing more than 175 lb (79 kg), both helical and nonhelical image quality degraded equally when 5-mm collimation was used; 10-mm collimation resulted in excellent image quality, regardless of patient size. Small in-plane structures (eg, renal arteries, renal veins, pancreatic duct) were seen best on helical scans. With the addition of retrospectively reconstructed overlapping images, improvement in visualization of these structures was statistically significant. CONCLUSION: Helical CT scanning should be the preferred means of acquiring routine abdominal CT images.

Abdominal Neoplasms↗
PubMed1993

Helical (spiral) CT of the abdomen.

Since its clinical introduction in the mid 1970s, techniques for CT have undergone many changes that have dramatically altered how CT scans are obtained. Helical (spiral) CT allows for faster acquisition of truly volumetric CT data than is possible with conventional scanners. Routine helical CT of the abdomen is now possible because of three major technical refinements: the development of the slip-ring gantry, improved detector efficiency, and greater tube cooling capability. This article reviews the technical principles that govern helical CT, the potential advantages and disadvantages of this technique, and initial clinical experience with helical CT of the abdomen.

Humans↗